Have you ever dated a very attractive person then felt insecure when you see someone who'd look better next to?

Say you're dating one of those people who is highly attractive. I mean extremely attractive including being in good shape! You're so into them and the feeling is mutual then you see a boy or girl who would just look adorable next to them. Even better than you think you look next to them. Ya know how some couples just look so adorable next to each other physically and it's hard to imagine them looking that great next to anyone else? Like they just look like they would have tthe most gorgeous daughters and the most handsome sons? I think you get the point lol anyway, how to deal with this? What did you do?